A genuine commitment to public health or a parents' revolt are two ways that may force the government to change its policy over school meals.
Tim Lang, professor of food policy at City University, told a Marketing Week conference on school meals in London last week that it would take a crisis to force change.
But, he believed the impetus was gathering momentum. There was concern in government about the "exploding" problem of obesity in the young. In particular, the Treasury could see a massive cost to the public purse if the current trend continued.
Today, one in five kids are classified as obese and diet-related illness costs the NHS £13b a year. Lang said the schools meals policy was in a mess - but three initiatives were possible.
"One would be for the government to show a genuine commitment to public health, another is a parents' revolt and another is for the inclusion of food and nutrition into Ofsted [the education watchdog].
"Not one parent I know wants their child to be fat and turn diabetic or die of heart disease before they do. I am biased, but I think that a health crisis will be the breaking of eggs that will make the omelette."
Prof Lang said the school meal service could be abandoned, completely privatised or rebuilt. He favoured the last option, but it had to be done in a new way, addressing a new agenda.
Dr Helen Crawley, nutritionist at London Metropolitan University, said the nutritional argument was painfully clear - there had been an explosion of obesity. She said fewer than half of children ate school dinners - the service had a bad image - and so more ate packed lunches, which were worse for kids than many school meals.
She said there should be a free school meal service. "I don't know why the government doesn't do it - it would be a massive vote-winner and it wouldn't cost that much.
"All public-sector catering, including prisons, hospitals and schools, needs proper quantifiable nutritional standards, so that those involved can say their menus meet the guidelines."
To achieve this, she said there should be a national food database to aid caterers.
Health campaign changes school menu in Scotland
A strong political will to change the health of the nation has driven reform of the school meal sector in Scotland, according to Fergus Chambers, director of Glasgow City Council.
He told the conference that the "hungry for success campaign", which started in November 2002, would spend an extra £63m on school meals over three years in an attempt to improve children's diet and make school meals popular again.
He said the key principle was that school meals in Scotland were no longer a commercial enterprise. "It is a vehicle to improve health and brings with it a lot of money and a lot of political and moral support."
The aim was to lift standards of health by meeting defined nutritional targets, which had to be met in primary schools by 2004 and in secondary schools by 2006.
Glasgow City Council embarked on its own campaign in 1996, which has seen some noticeable changes in schools, including a ban on branding of unhealthy food and drink.
"We still sell Coca-Cola, but we don't do it out of a Coca-Cola cup," said Chambers. "For those who say we shouldn't sell Coca-Cola at all, my experience is that if you tell a child what they can't have, they will vote with their feet."
He said previous research pointed to queues as the "number one reason" why school meals were unpopular. In Glasgow, schools had tried to address this by introducing multi-service points.
Chambers said the new campaign had been well received, but it was too early to say it was a success. "We are becoming far better at making the service more attractive."
Usage has doubled in some areas.
School meals
- One in five kids are classified as obese
- Less than half children eat a school meal
- Diet is too high in fat and too high in sugar
- Children hate queues
- Lunch breaks are getting shorter
- Pack lunches are nutritionally inferior
Kids want happy staff and food that looks good
Children like happy catering staff, quick queues and food free of foreign objects, according to the latest research.
Jonathan Aitwood, chief executive of SwapitShop, an online swap-shop for kids, said the company's poll of 1,000 children pulled out some common strands. "Consistently, kids said their food was soaked in fat and grease and their vegetables were sloppy and mushy. They want food that looks good. "
Aitwood added that kids wanted good-tasting food. "They want to eat it in a good area and they like events and promotions, such as Christmas lunch."